The invention concerns a continuous casting installation, especially for the continuous casting of thin slabs, which has a vertically oriented strand guide arranged below a mold and in which means for driving the cast strand and bending it into the horizontal direction are arranged below the strand guide. The invention also concerns a method for operating a continuous casting installation.
Continuous casting installations of this type are sufficiently well known in the prior art.
The starting point for continuous casting installations of this type are curved mold continuous casting machines or vertical bending installations with a casting radius of generally seven to twelve meters for relatively large casting thicknesses, at which the strand with a liquid core is bent and straightened.
The term “CSP” (Compact Strip Production) denotes a continuous casting process for thin slabs, which usually have a thickness of 45-70 mm and occasionally up to 90 mm. In this case, the vertical type of installation construction is widely used, in which the cast strand is not bent and straightened until after it has thoroughly solidified. An advantage of CSP plants is that the design of the plant can be kept simple, especially where the strand guide is concerned. For example, in the event of a strand breakout below the mold, the mold and the affected members of the strand guide can be removed and replaced from above with a crane. In this type of plant, much less work is required for making the change and thus the associated loss of production is smaller than when standard curved segments are used, which cannot be removed from above.
Another advantage is that the strand is not bent and straightened until it has completely solidified. Therefore, the strand expansions are smaller; there is no need to fear that the sensitive inner side of the strand will be torn up.
FIG. 1 shows a prior-art continuous casting installation 1 of this type. Cast steel moves vertically downward from a mold 2, and the strand 6 produced in this way is guided along a strand guide 3. By the time the strand 6 leaves the lower end of the strand guide 3, it is essentially completely solidified. Below the strand guide 3, the strand 6 enters an area that is equipped with means 4, 5 for the combined driving and bending of the strand 6. As the drawing shows, in the direction of its conveyance, the strand 6 first passes through two bending drivers, which both drive the strand 6 in the direction of conveyance and act on it with bending forces. The rolls of the bending driver 4, 5 are set by a displacement device 11. The following rolls bend the strand further towards the horizontal H. Finally, the strand 6 leaves the installation in the horizontal direction H and is conveyed further to suitable downstream installations. The cooling chamber 12 for cooling the strand 6 is only schematically illustrated.
In accordance with the above explanations, it is desirable that the available height of the strand guide should be as great as possible and, for a given installation height, the height at which the bending of the strand occurs should be as low as possible, for in this way the maximum path is available for the complete solidification of the strand along the strand guide.
Therefore, the objective of the present invention is to further develop a continuous casting installation of the type described at the beginning and to develop a suitable method for operating a continuous casting plant in such a way that it is possible to use the greatest possible height of the strand guide at the lowest possible height for the driving, bending, and straightening of the cast strand. The region of the driving and bending is thus to be shortened in favor of a lengthened strand guide. A further objective of the present invention is to create the favorable possibility of being able to eliminate disruptions and carry out repair and maintenance work as quickly and efficiently as possible. The lengthening of the strand guide is intended to increase the productivity of the plant.